Four Rare Guam Kingfisher Chicks Hatch at Virginia Facility, Making an ‘Incredibly Valuable’ Addition to the Small Population of Extinct-in-the-Wild Birds

The species, also known as the sihek, was wiped out from its native Guam and kept alive in captivity. Conservationists released some birds on Palmyra Atoll in 2024, and they have been thriving so far

Carlyn Kranking | Associate Web Editor, Science

May 29, 2026 5:00 p.m.

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Extinct from their native habitat in the wild, the Guam kingfisher, or sihek, is an extremely rare bird. But this spring, its numbers got an important boost.

Four new sihek chicks have hatched at the Smithsonian Conservation Biology Institute in Front Royal, Virginia, with the first two hatchlings emerging from their eggs on April 12 and April 14 and the second two on May 27 and May 28. Their parents are 2-year-old Poki and 5-year-old Antonio, and neither bird had bred before.

The hatchlings mean the facility has met its record of four sihek chicks in a season, previously set in 2020 and 1985. Now, 33 sihek chicks have hatched at the Conservation Biology Institute over the years. And across the planet, only about 125 sihek are living today.

“Given the small size of the worldwide population of sihek, every additional individual is incredibly valuable,” Megan Laut, a wildlife biologist with the United States Fish and Wildlife Service, tells Smithsonian magazine. “Young birds are important to replace birds that are no longer part of the breeding population. They are the next generation.”

On their native Guam, sihek—and many other endemic species—were wiped out by the invasive brown tree snake, introduced to the island after World War II, potentially through military cargo ships. With no natural predators around, the snakes multiplied and hunted birds, lizards and bats. Ten of the island’s 12 forest bird species were eliminated from the wild by the reptiles. Some of those birds, like the ko’ko’, or Guam rail, and the sihek, endure today only because of captive breeding programs.

“Caring for Guam sihek can be quite challenging at times,” says Erica Royer, an aviculturist at the Smithsonian’s National Zoo and Conservation Biology Institute, who is looking after the new chicks, to Smithsonian magazine. “They are a territorial little bird, so the pairs can be difficult to breed. The parents of these two chicks did not get along last year, but this year they decided it was their time.”

First-time parents Poki and Antonio both came to the Conservation Biology Institute from other zoos for breeding. But because they do not have chick-rearing experience, keepers decided to take charge of incubating the eggs and raising the hatchlings to boost the birds’ chance of survival.

This meant that while keepers incubated the real eggs, they gave Poki and Antonio “dummy eggs,” or sihek eggshells filled with plaster, to practice on. As the bird parents honed their incubation skills, the animal care team made sure their real eggs were warmed to a specific temperature, hand-turned and kept at the right humidity, based on daily weight measurements. Hatchlings have to be fed by staff seven times per day and are gradually weaned to fewer feedings. Right now, the team is working on getting the April hatchlings to eat on their own, “but they are a bit picky still,” Royer says.

Because the chicks come from first-time parents, their genes are not well-represented in the world’s small sihek population. That’s good news for conservation, because it means that their future breeding will help promote genetic diversity in the pool of living birds, Laut adds.

Ultimately, the birds raised in zoos—or their descendants—could make a highly anticipated return to the wild, as some sihek already have. While control efforts have decreased the invasive brown tree snake’s population on Guam, the predator has not yet been eradicated. So, rather than reintroduce sihek to their native island, conservationists chose to translocate the birds to another wild site: Palmyra Atoll. Located within the protected Palmyra Atoll National Wildlife Refuge, the chain of 26 islets has been cleared of invasive species, so the birds would enjoy a predator-free haven.

Conservationists released nine sihek—five males and four females—in September 2024. The project brings together experts from many groups, including the Guam Department of Agriculture, the Association of Zoos and Aquariums, the Nature Conservancy, the U.S. Fish and Wildlife Service and the Zoological Society of London.

“Based on similar conservation translocations of birds, we would expect about 50 percent survival of released individuals,” Royer says. “We still have 100 percent survival.” Better yet, the birds are attempting to breed.

In late March 2025, biologists discovered sihek eggs in a nest on Palmyra Atoll, making them cautiously optimistic about the birds’ ability to thrive in the wild. In the end, none of the eggs hatched, but this could just be due to the parents’ inexperience: “This was their first time caring for their eggs, and it is anticipated that it may take a few more attempts for the birds to mature their skills and successfully hatch and rear chicks,” according to the U.S. Fish and Wildlife Service.

“We are hopeful that we’ll soon have our first wild chick in almost 40 years as these birds grow a bit older and gain more parenting experience,” John Ewen, a professor in species recovery at the Zoological Society of London’s Institute of Zoology, tells Smithsonian magazine. “We are also working on sending another group of sihek to Palmyra Atoll.”

Given the birds’ rarity, every new hatchling is something special, experts say. The sihek is culturally important to the Indigenous CHamoru people of Guam, and ecologically, it played a key role in managing insect and lizard populations. With the help of humans, the sihek has weathered existential threats, making the bird a powerful symbol of fragility and resilience.

“They are both a legacy of what can go wrong if we don’t care for nature but also what can be achieved when we decide to act,” Ewen says. “Conservation works—even in the most extreme of situations.”

Carlyn Kranking | | Read More

Carlyn Kranking is Smithsonian magazine's associate web editor for science.